export default {
	// 为当前模块开启命名空间
	namespaced: true,
	
	//模块的state 数据
	state: () => ({
		cart: JSON.parse(uni.getStorageSync('cart') || '[]'),
	}),
	
	//模块的mutations方法
	mutations: {
		addToCart(state, goods) {
			const findResult = state.cart.find((x) => x.goods_id === goods.goods_id)
			
			if (!findResult) {
				state.cart.push(goods)
			} else {
				findResult.goods_count++
			}
			
			//通过commit方法，调用saveToStorage方法
			this.commit('m_cart/saveToStorage')
		},
		//将购物车中的数据持久化到本地
		saveToStorage(state) {
			uni.setStorageSync('cart', JSON.stringify(state.cart))
		},
		//更新购物车中的勾选状态
		updateGoodsState(state, goods) {
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
			
			if (findResult) {
				findResult.goods_state = goods.goods_state
				this.commit('m_cart/saveToStorage')
			}
		},
		updateGoodsCount(state, goods) {
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
			
			if(findResult) {
				findResult.goods_count = goods.goods_count
				this.commit('m_cart/saveToStorage')
			}
		},
		removeGoodsById(state, goods_id) {
			state.cart = state.cart.filter(x => x.goods_id !== goods_id)
			
			this.commit('m_cart/saveToStorage')
		},
		updateAllGoodsState(state, newState) {
			state.cart.forEach(x => x.goods_state = newState)
			
			this.commit('m_cart/saveToStorage')
		}
	},
	
	//模块的getters属性
	getters: {
		//统计购物车中的总数量
		total(state) {
			let c = 0
			//循环统计商品的数量
			state.cart.forEach(goods => c += goods.goods_count)
			return c
		},
		checkedCount(state) {
			return state.cart.filter( x => x.goods_state).reduce((total, item) => total += item.goods_count, 0)
		},
		checkedGoodsAmount(state) {
			return state.cart.filter(x => x.goods_state)
							 .reduce((total, item) => total += item.goods_count * item.goods_price, 0)
							 .toFixed(2)
		}
	},
}